Final answer:
All of the listed organisms (amoebae, yeast, holly, and starfish) are eukaryotes because they have cells with a nucleus enclosed by membranes as well as various other organelles.
Step-by-step explanation:
Eukaryotes are characterized by cells that contain a nucleus enclosed within membranes. Unlike prokaryotic cells, eukaryotic cells also contain various membrane-bound organelles. For example, amoebae are single-celled organisms with complex cellular structures including a nucleus.
Yeasts are also single-celled but share similarities with higher organisms, like humans, in certain regulatory mechanisms. Plants, such as the holly, are multicellular eukaryotes with cells that contain chloroplasts as well as a nucleus. Lastly, starfish, as animals, are multicellular eukaryotes comprising complex tissues and organ systems, all made of cells with a nucleus and other organelles.